- Heat oven to 100 degC. Line two baking trays with nonstick baking paper.
- Place egg whites in a clean bowl and whisk until soft peaks of mixture hold their shape.
- Add sugar, a tablespoonful at a time, whisking continuously. Whisk for a further minute or two until the mixture is stiff and glossy.
- Fold in the sifted cocoa powder to just combine.
- Spoon mixture into mounds on prepared trays, then bake for 1½ hours until the meringues are hard and dry.
- Remove from oven and leave to cool completely.
- Serve meringues with whipped cream on the side.
- Store hard meringues in an airtight container for up to four days.